Update gate jobs as per the 2025.1 cycle testing runtime
As per 2025.1 testing runtime[1], we need to test on Ubuntu
Noble (which will be taken care by depends-on tempest and devstack
patches to move base jobs to Noble) and at least single job to run on
Ubuntu Jammy (for smooth upgrade from previous releases).
This commit adds a new job to run on Jammy which can be removed
in future cycle when testing runtime test next version of Ubuntu
as default.
Remove default override for config options policy_file
olso.policy 4.5.0[1] changed the config options policy_file
default value to 'policy.yaml', which means it is changed
for all the OpenStack services and they do not need to
override the default anymore.
NOTE: There is no change in behaviour here, oslo.policy provides
the same configuration that services have overridden till now.
